1. Field
The present disclosure is generally related to choosing a billing structure for printing a document based on an electronic file, and, in particular, to a system and method for determining a billing structure for outputting documents based on an estimated amount of marking medium (toner or ink) needed to print the document.
2. Description of Related Art
Image data comprises a number of pixels having a number of components that contribute to defining the image, such as color and intensity. The image data generally includes various color or gray levels, which contribute to the intensity of each pixel in the image. Each pixel of the image is assigned a number representing the amount of light or gray level for that space at that particular spot; i.e., the shade of gray in the pixel. Binary image data has two possible values for each pixel, black (represented by the number “1”) or white (represented by the number “0”). Images that have a large range of shades are referred to as grayscale images. For example, grayscale images have an 8-bit value (or higher) per pixel comprising 256 tones or shades of gray for each pixel in the image (gray level of 0 to 255). Grayscale image data may also be referred to as continuous tone or contone image data. The pixels in a color image may be defined in terms of a color space, typically with three values, such as RGB—R for red, G for green, and B for blue—or four values, such as CMYK—C for cyan, M for magenta, Y for yellow, and K for black, or composite black.
The pixels may also be defined in terms of device independent space (e.g., when inputting image data, such as standard RGB (sRGB) or CIE L*a*b*) or a device dependent space (e.g., when outputting image data, such as RGB or CMYK). When outputting image data to an output device (e.g., copier, printer, or multi-function device (MFD)), printing documents using black ink or toner is generally less expensive than using colored ink or toner. Thus, billing is often based on the amount of color content contained in the job to be printed. In order to bill customers for color printing, color detection is an important feature required in an image path. Color detection is used to analyze documents for presence of color as well as an amount of color in order to bill customers accordingly. Generally, the higher the presence and amount of color in a document, the higher the cost.
Some systems include counting the number of pixels in the image data of the document to be printed. Some available techniques are based on an area coverage methodology developed for offset presses, or are based on comparisons to a small set of documents with measured area coverage. For example, in offset printing, ink estimates were based off of the area of the exposed plate, i.e., measured area coverage (or percentage) for printing a page. Several ad hoc extensions to offset tools have been developed. However, such tools can be highly inaccurate. Some versions of these available tools may produce answers varying by different factors when processing the same document. For example, the Xerox® 490/980 color printing system can show the customer (e.g., via an interface) multiple one page documents and their predicted area coverages which are predicted by running the document through a complete machines simulator program. Such predicting, however, can require an ample amount of time (e.g., one day per page). Then, to estimate toner usage to a given job, the customer is asked to choose the document closest to his job, or to interpolate between the multiple presented documents. This may produce inaccurate estimations each time a document or page is printed. Similarly, third party plug-ins used to analyze documents may also give unrealistic results.
For digital print systems, such as Xerographic systems, the relationship between the exposed image and the toner/ink used for printing a page or document may be much more complex. This may include extensive simulation and some knowledge of the actual machine parameters to predict toner/ink usage. Edge enhancement, developer age, and separation to separation interactions can also make estimating toner usage difficult. In some large production systems, large sumps and well-buffered toner delivery systems translate to thousands and/or tens of thousands of pages that must be printed before getting reliable toner/ink usage numbers.
Digital printers are reaching higher speeds for output and lower per page costs. The actual toner/ink usage is becoming a larger part of the total cost of a print job. As challenges in digital printing are offset by longer runs, a more precise estimation of print costs for a print system may be desirable. For example, previous estimations of per page print jobs may have underestimated the cost for an amount of toner/ink to output a page. In current systems, toner or ink can easily constitute 70% of the per page print cost.
Accordingly, an improved system and method of determining the amount of toner/ink for printing a document and correctly billing customers is desirable.